In substrates for hard discs, cleaning of the discs has been performed after the after processes such as grinding, polishing, spattering and plating therefor. For the cleaning of discs such as hard discs and wafers, a plurality of cleaning processes and drying processes after the cleaning are provided. As one of the cleaning processes, scrub cleaning by a scrub cleaning device is exemplified.
As another cleaning process, a device is known in which a carrier (or tray) aligning a plurality of discs vertically thereon is immersed in a bath filled with cleaner liquid and then the discs are cleaned by ultrasonics. In this instance, the drying of the discs after the cleaning is performed after the carrier (or the tray) is transferred to a drying chamber.
In place of such carrier cleaning, a device is known in which conveyers are respectively provided in a shower bath, chemical bath, an ultrasonics bath and a pure water bath, and discs are cleaned by being transferred by the conveyer in the respective baths and successively moved between the respective baths. Further, in this instance, a scrub cleaning device can be disposed prior to the shower bath.
As a scrub cleaning device, JP-A-11-129349 discloses one which cleans discs while catching the discs between adjacent circular plate brushes mounted on a rotary shaft. The device discloses a technology in which many numbers of the circular plate brushes are continuously mounted on the rotary shaft with a gap and assembled as rotatable brushes and the scrub cleaning is performed while catching a part of each disc in the gap between circular plate brushes and rotating the many discs together with the circular plate brushes.
Further, for the brushes in the scrub cleaning, brushes of porous sponge member have been used and the cleaning is performed by contacting the same on the surfaces of rotating discs. In the present specification and claims, the term “brush” of course covers such a sponge member.
The present assignee filed an application relating to a disc cleaning device in which numerous circular plate brushes are continuously mounted and stacked along on the axis of a rotary shaft and scrub cleaning of discs is performed while catching the discs between adjacent circular plate brushes as U.S. patent application Ser. No. 11/548,841, now U.S. Pat. No. 7,841,035 (which corresponds to JP-A-2007-105624, JP-A-2007-117897 and JP-A-2007-289878) and is known in public. This application discloses a technology in which separate from the discs to be cleaned, brush cleaner circular plates for cleaning the brushes are inserted between the circular brushes and the circular brushes are cleaned at the same time when the discs are cleaned.
JP-A-9-29188 discloses a scrub cleaning device in which instead of stacking the circular plate brushes in a rotary shaft, many numbers of pairs of circular plate brushes are provided on a rotary shaft and each opens and closes in the axial direction thereof, and is known in public. In the device, other than shower injecting cleaner liquid to discs, cleaner liquid is flowed through the rotary shaft and the cleaner liquid is fed from the side of the rotary shaft to the circular plate brushes to clean the discs.
In the scrub cleaning device in which many numbers of circular plate brushes are stacked along on the rotary shaft and the discs are cleaned while catching the discs between adjacent circular plate brushes, there arises a problem that dirt is likely to accumulate between the circular plate brushes or dirt is likely to remain on the brushes. For this reason, cleaning of the brushes is necessitated.
In the technology as disclosed in U.S. patent application Ser. No. 11/548,841, now U.S. Pat. No. 7,841,035, the brush cleaner circular plate is provided with holes or slits, is inserted between adjacent circular plate brushes and is rotated together with the discs, whereby cleaning of the circular plate brushes is effected at the same time when the discs are cleaned. However, dirt material or dirt scum caught between the circular plate brushes is hard to remove. The reason for this is thought that since the gap between the circular plate brushes of porous sponge is narrow or both are closely positioned, it is difficult to scrub out the dirt material or the dirt scum, even when the brush cleaner circular plates are inserted therebetween. For this reason, problems arise that the disc cleaning efficiency decreases, parts of brush faces are likely to wear and the exchange frequency of the circular plate brushes increases.
Therefore, it is conceived to clean the circular plate brushes by feeding cleaning liquid to the circular plate brushes from the side of the rotary shaft by making use of the technology disclosed in JP-A-9-29188. However, since it is difficult to open and close the stacked circular plate brushes in the axial direction, even if the cleaning liquid is fed to the circular plate brushes from the side of the rotary shaft, the dirt material or the dirt scum deposited between the circular plate brushes cannot be removed by the cleaner liquid fed to the circular plate brushes from the side of the rotary shaft and cleaning of the circular plate brushes themselves cannot be effected sufficiently.